1. Field of the Invention
The present invention relates to a method for compensating laser energy of optical disk drive, more particularly a method used for the laser light source energy adjustment of an optical disk drive and the optimal light source energy compensation control.
2. Description of the Prior Art
As the Optical disk drive is widely used in audio and video equipments in our daily life and computers information equipment as well, serving as the major equipment for playing the audio and video data and reading data from the computer. However, the components of the mechanism of the optical disk drive used for reading or writing data are illuminated laser components such as the prior-art CDR/W. The intensity of the light source for the illuminating laser component determines the quality of reading and writing data; therefore the adjustment of the illuminating parameters of the laser components becomes extremely important.
The direct electric power relation value for the laser components"" illumination of a traditional optical disk drive is measured in milliwatt (mw), which uses the unit of power to represent its output brightness or output parameter, and the whole laser component""s illumination parameter is measured in milliwatt/ampere (MW/A) to represent its relative relation of output with respect to its input. Such value is generally considered as an electric voltage and under normal conditions, the laser light source energy (brightness) is always directly proportional to the value of the illumination parameter. In other words, when there is no run-out, the larger the value of illumination parameter, the larger is the emission of the laser light source energy.
In fact, the operation of the laser components in the optical disk drive is not as ideal as mentioned above. In FIG. 7, it shows the energy distribution of the laser light source of the optical disk drive. Since assembly relation of the laser component X and the lens Y of the optical disk drive is not completely free of interference. For example, the shifting of the lens Y in installation causes the disturbance problem of the shifted focus, or the disturbance factor due to the assembly between the servomotor of the optical disk drive and the optical disk, which will directly affect the intensity of the light source emitted from laser component X. Most of them are due to the shift factor of the lens Y. In FIG. 6, it shows the shift of light source energy caused by the reflection points A1, A2, and A3. We can see that the intensity of the light source at the reflection point A2 is stronger than those at A1 and A3. If using a function to present it, then the illumination parameter PW=F(P, Offset), which is a function containing the shift disturbance factor for the lens Y assembly.
FIG. 8 further discloses the curve that shows the relative energy loss caused by the shifting of the lens Y assembly by the laser light source, wherein it is obvious that no matter it is from the lens curve PHO, we can clearly see the illumination parameter curve RRF, light source feedback curve BHO, and the power input curve PLT. The energy loss at the reflection point A2 as shown in FIG. 6 is the smallest, and the energy losses at reflection points A1 and A3 are relatively the largest. In other words, the light source energy (brightness) at the reflection point A2 is the largest, but it does not mean that its input illumination parameter PW is the largest. FIGS. 9 to 12 respectively show the light source feedback curve BHO, power input curve PLT, illumination parameter curve RRF, and the waveform diagram of the input power FPDO for the laser component X and provide us with proofs. The light source energy intensity at reflection points A1, A2, and A3 will be affected by the disturbance factor of the shift lens Y assembly generating a disturbance change to the relation between the power parameter PW and the light source energy. It is unable to directly find the power parameter PW at an optimal light source energy point, which causes errors or insufficient light source energy when the optical disk is reading or writing data, and even causes failure in writing data or skipping tracks.
In addition, the prior art optical disk drive industry solves this problem by inspecting and adjusting the drive on the production line. Inspection and adjustment by labor force not only wastes time, labor force, and cost, but also cannot comply with the economic efficiency for the production. The adjustment to the light source energy totally depends on the personal experience of the professional staff, and the shift condition for the lens Y assembly of each optical disk drive is not the same, and it cannot let all of the products be accurately adjusted to the best illumination energy output conditions which causes uneven quality of the product, and seriously affects the stability and quality of the optical disk drive products.
The primary objective of the present invention is to provide a method for compensating the laser energy for optical disk drives, capable of accurately finding the maximum laser light source energy that eliminating the run-out for the lens assembly and its relative illumination parameter such that it puts the illumination energy into full play when the laser component writes in or read out data.
A further objective of the present invention is to provide a method for compensating the laser energy for optical disk drives, which can automatically find the optimal illumination parameter for the illumination energy under the run-out factor for any different lens assemblies.